Radiant Furniture

ABSTRACT

Radiant furniture made of a concrete mix includes one or more heating elements or hot water supplied hydronic tubing that provide comfortable radiant heat. Tabletops can be heated to a temperature that is comfortable for people seated at the table. Benches and seats can be heated to provide comfortable heated seating. Combinations can also be used together, such as a heated tabletop with heated seats. A controller senses the temperature of the furniture and the ambient temperature, then applies power to one or more heating elements in the furniture according to programmed temperature thresholds to provide comfortable radiant heat from the furniture. The controller includes a calibration mode that allows calibrating the controller to a particular heated surface. The controller further comprises a knob that determines an operating mode for the controller and allows adjusting a temperature threshold for the heated surface up or down.

BACKGROUND 1. Technical Field

This disclosure generally relates to furniture, and more specificallyrelates to furniture that radiates heat.

2. Background Art

Many restaurants include outside seating. When the weather is cool orcold, portable space heaters are often used to keep the outside dinerswarm. For example, large, umbrella-shaped propane heaters are often usedto keep the outside dining area warm when the temperature outside iscool or cold. A problem with these types of heaters is people closest tothe heaters are often too warm and people a little farther away from theheaters are often too cold. This is because these heaters are designedto heat a given space, not specifically people within the space. Inaddition, these heaters can be expensive to run, hot to the touch andtherefore a burn hazard, difficult to light, require periodicmaintenance, etc. There exists a need for a heater that providescomfortable heat for people in a given space without the drawbacksmentioned above, in both commercial and home patio settings.

SUMMARY

Radiant furniture made of a concrete mix includes one or more heatingelements or hot water supplied hydronic tubing that provide comfortableradiant heat. Tabletops can be heated to a temperature that iscomfortable for people seated at the table. Other tabletops can beheated to a lower temperature for use in a greenhouse. Benches and seatscan be heated to provide comfortable heated seating. Combinations canalso be used together, such as a heated tabletop with heated seats. Acontroller senses the temperature of the furniture and the ambienttemperature, then applies power to one or more heating elements in thefurniture according to programmed temperature thresholds to providecomfortable radiant heat from the furniture. The controller includes acalibration mode that allows calibrating the controller to a particularheated surface. The controller further comprises a knob that determinesan operating mode for the controller and allows adjusting a temperaturethreshold for the heated surface up or down.

The foregoing and other features and advantages will be apparent fromthe following more particular description, as illustrated in theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING(S)

The disclosure will be described in conjunction with the appendeddrawings, where like designations denote like elements, and:

FIG. 1 is a perspective view of a table with a tabletop that radiatesheat;

FIG. 2 is a bottom view of the tabletop shown in FIG. 1 showing a singleheating element embedded within the concrete mix of the tabletop;

FIG. 3 is a cross-sectional view of the tabletop in FIG. 2 taken alongthe line 3-3;

FIG. 4 is a block diagram of radiant furniture that uses electricconduction heating elements;

FIG. 5 is a flow diagram of a method for a controller to control radiantfurniture that includes a single heating element, such as the tabletopshown in FIGS. 1-3 ;

FIG. 6 is a bottom view of a second embodiment for the tabletop shown inFIG. 1 showing two heating elements embedded within the concrete mix ofthe tabletop;

FIG. 7 is a cross-sectional view of the tabletop in FIG. 6 taken alongthe line 7-7;

FIG. 8 is a flow diagram of a method for a controller to control radiantfurniture that includes two heating elements, such as the tabletop shownin FIGS. 6-7 ;

FIG. 9 is a flow diagram of a method for adjusting temperaturethresholds when ambient temperature is below a specified adjustmentthreshold;

FIG. 10 is a bottom view of a third embodiment for the tabletop shown inFIG. 1 showing a heating element embedded within the concrete mix of thetabletop with the center of the tabletop not having any heating element;

FIG. 11 is a block diagram of radiant furniture that uses heating tubesthrough which hot water is circulated;

FIG. 12 is a block diagram of a second suitable embodiment of radiantfurniture that includes a controller that controls temperature of one ormore heated surfaces in the radiant furniture;

FIG. 13 shows a knob that can be used to vary the function of thecontroller logic 1240 shown in FIG. 12 ;

FIG. 14 is a table of temperatures for three different operating modesfor the controller logic, including temperature thresholds for when theknob is in the ON position, and for a number of different ambienttemperatures when the knob is between the OFF and the ON position;

FIG. 15 is a flow diagram of a method for calibrating the controllerlogic 1240 in FIG. 12 to heat a heated surface in radiant furniture;

FIG. 16 is a flow diagram of a method for heating a heated surface inradiant furniture;

FIG. 17 shows one suitable configuration for heating element runs in around tabletop;

FIG. 18 shows one suitable configuration for heating element runs in around tabletop that has an open inner portion or that has no runs ofheating element in the inner portion;

FIG. 19 shows one suitable configuration for heating element runs in arectangular tabletop;

FIG. 20 shows one suitable configuration for heating element runs in arectangular tabletop that has an open inner portion or that has no runsof heating element in the inner portion;

FIG. 21 shows a first suitable configuration for heating element runs ina heated seating panel;

FIG. 22 shows a second suitable configuration for heating element runsin a heated seating panel;

FIG. 23 shows a heated couch;

FIG. 24 shows a left end view of the heated couch in FIG. 23 with thestructural frame removed for the sake of clarity;

FIG. 25 shows the left end view of the heated couch in FIG. 23 when theback cushion is pivoted down to overlie the bottom cushion;

FIG. 26 is a side cross-sectional view of the items shown in FIG. 25 toshow their construction for one specific implementation;

FIG. 27 is a side cross-sectional view of the items shown in FIG. 24 toshow their construction for one specific implementation;

FIG. 28 is a side cross-sectional view of an alternative embodiment forthe back cushion that includes a fixed portion and a movable portion,with the movable portion in a lower position overlying the bottomcushion; and

FIG. 29 is a side cross-sectional view of the alternative embodimentshown in FIG. 28 with the movable portion in an upper position next tothe fixed portion.

DETAILED DESCRIPTION

The disclosure and claims herein relate to radiant furniture made of aconcrete mix that includes one or more heating elements or hot watersupplied hydronic tubing that provide comfortable radiant heat.Tabletops can be heated to a temperature that is comfortable for peopleseated at the table. Other tabletops can be heated to a lowertemperature for use in a greenhouse. Benches and seats can be heated toprovide comfortable heated seating. Combinations can also be usedtogether, such as a heated tabletop with heated seats. A controllersenses the temperature of the furniture and the ambient temperature,then applies power to one or more heating elements in the furnitureaccording to programmed temperature thresholds to provide comfortableradiant heat from the furniture.

Referring to FIG. 1 , a table 100 includes a radiant tabletop 110 thatradiates heat in all directions, as shown by the arrows emanating fromthe tabletop 110. The tabletop 110 is connected to a support 120 that isconnected to a base 130. Providing a radiant tabletop 110 allows aperson seated at the table to maintain a comfortable temperature. If theperson feels cold, the person can move closer to the tabletop 110 orlean over the tabletop 110 to take advantage of the heat radiating fromthe tabletop 110. If the person feels warm, the person can sit back inhis or her chair farther away from the tabletop 110 to be farther awayfrom the radiant tabletop 110. A table 100 with a radiant tabletop 110thus allows a user to easily regulate the amount of heat they feel bymoving closer to or farther from the radiant tabletop 110.

Radiant tabletop 110 is preferably made of a concrete mix. Concrete is apreferred material for radiating heat. The term “concrete mix” as usedherein means any mix that includes a dry powder binder (such as Portlandcement) that together with a liquid forms a paste that is combined withsand and/or aggregate of any suitable size. One preferred mix ismarketed under the brand name enCOUNTER, which is a specialized concretemix generally used to make concrete kitchen countertops. This mix has aspecified compression strength of 8,700 pounds per square inch (psi)(612 kg per square cm). The enCOUNTER, concrete mix provides heavydensity, high strength radiant furniture with no warping or long-termcracking issues. Bags of enCOUNTER are 50 lb (22.7 kg), and areavailable in either gray or white. The white enCOUNTER mix has lesscoarse aggregate than the gray enCOUNTER mix. One suitable mix for theradiant furniture is:

50 lb (22.7 kg) enCOUNTER mix82 to 90 fluid ounces (2.4 to 2.7 liters) water

Other ingredients could be added to the mix, including plasticizer andstructural fiber. A suitable plasticizer is enFLOW plasticizer, and asuitable structural fiber is enFORCE. The enCOUNTER mix, enFLOWplasticizer and enFORCE fibers are all made by the same company as partof the enCOUNTER product line, and are available from Cimarron Wholesalein Oklahoma City, Okla. One suitable mix for the radiant furniture thatincludes the plasticizer and structural fiber is:

50 lb (22.7 kg) enCOUNTER mix64 to 72 fluid ounces (1.9 to 2.1 liters) water1 fluid ounce (0.03 liter) enFLOW plasticizer2 dry ounces (60 grams) enFORCE structural fibers

Other alternatives could be used instead of the enCOUNTER mix, includingXtreme Countertop available from SureCrete Design in Dade City, Fla.;Sakrete 5000 available from Bonsal American, Inc. in Charlotte, N.C.;and Cheng Pro-Formula Concrete Countertop Mix available fromstore.concreteexchange.com.

Of course, a suitable mix for the radiant furniture could be madewithout using one of the commercially-available mixes above. Onesuitable mix for the radiant furniture is:

10 lb (4.5 kg) Portland cement14 lb (6.4 kg) sand (or fine aggregate of several sizes)12.5 lb (5.7 kg) coarse aggregate (such as white limestone)2.5 to 4.8 lb (1.1 to 2.2 kg) water

One suitable enhancement to the mix above is the addition of metakaolin,which is a dehydroxylated form of the clay mineral kaolinite. Metakaolinis generally considered a replacement for Portland cement, at aproportion of 8-20% of the weight of the cement. Metakaolin can increaseboth the compressive and flexural strength of concrete. A suitable mixfor the radiant furniture that includes metakaolin is:

9 lb (4.1 kg) Portland cement1 lb (0.5 kg) metakaolin14 lb (6.4 kg) sand (or fine aggregate of several sizes)12.5 lb (5.7 kg) coarse aggregate (such as white limestone)2.5 to 4.8 lb (1.1 to 2.2 kg) water

While several specific formulations of the concrete mix are disclosedabove, one of ordinary skill in the art will realize that a suitableconcrete mix can have ingredients with weights or proportions that varyfrom those disclosed above. For example, the weight or proportion ofeach ingredient could preferably vary by as much as 30% in accordancewith the disclosure and claims herein. The weight or proportion of eachingredient could more preferably vary by as much as 20% in accordancewith the disclosure and claims herein. The weight or proportion of eachingredient could still more preferably vary by as much as 10% inaccordance with the disclosure and claims herein. And the specificweights and proportions disclosed above are the most preferred weightsand proportions for the concrete mix.

The support 120 and base 130 could be made of any suitable materialcapable of structurally supporting the tabletop 110, including concrete,wood, metal, or any other natural, synthetic or composite material. Inone particular implementation, the support 120 and base 130 are made ofthe same concrete mix as the tabletop 110. To keep from losing heat, thetabletop 110 can be thermally insulated from the support 120. In thealternative, the tabletop 110 can be thermally coupled to support 120,which will allow heat to travel from the tabletop 110 into the topportion of the support 120.

A concrete mix is the preferred material for radiant tabletop 110because a concrete mix can provide the thermal mass and heat conductionproperties that work well when embedding heating elements in theconcrete mix. In the most preferred implementation, the concrete mix isa high-strength concrete mix that has a compressive strength of at least6,000 psi (422 kg per square cm). Note, however, that many othersuitable materials could be used, including without limitation bothnatural and synthetic materials. For example, an epoxy resin orpolyurethane could be used instead of a concrete mix, but may provideless heat conduction when compared to a concrete mix when they have lessdensity than a concrete mix. The disclosure and claims herein expresslyextend to the use of any suitable material for the heated surface ofradiant furniture. When a concrete mix is used for the heated surface,the concrete mix provides a concrete substrate into which a heatingelement and a temperature sensor may be embedded to form the heatedsurface.

The radiant heat in the tabletop 110 is created by applying power to oneor more heating elements embedded within the concrete mix of thetabletop 110. FIG. 2 shows a bottom view of the tabletop 110 withoutmost of the concrete so the heating element 210 is visible. Heatingelement 210 is most preferably a conduction heating element thatproduces heat by current passing through one or more resistive elements,causing the heating element to radiate heat. Heating element 210 ispreferably a commercially-available heating cable that is manufacturedby Watts Water Technologies in Springfield, Mo. as ProMelt model numberSC50120008 for a 29 ft cable and SC50120053 for a 208 ft cable, withother lengths available in between these two lengths. This product isused for ice-melt applications in flatwork, so sidewalks, driveways,etc. can have snow or ice easily cleared by heating the heating cableembedded in the sidewalk or driveway. The heating element 210 ispreferably designed for single-phase operation. Thus, for applicationsin the United States, the heating element 210 is preferably designed tobe powered by a 120 volt alternating-current power source. Of course,other voltages could also be used, and two-phase or three-phase ordirect-current (DC) power could also be used within the scope of thedisclosure and claims herein. The specified minimum bend radius is oneinch (25 mm). When the heating element is spaced at 3 in. (7.6 cm)centers, it is rated at 50 watts per square foot (540 watts per squaremeter). When spaced at 2 in. (5.1 cm) centers, it is rated for 75 wattsper square foot (810 watts per square meter). The spacing of the heatingelement within the tabletop 210 can thus be varied to create differenttabletops with different heating properties. For example, a table usedin a greenhouse for sprouting plants may need to maintain a temperatureof only 80 degrees Fahrenheit (27 degrees Celsius), while a table usedin an outside area of a restaurant may need to maintain a temperature of105 degrees Fahrenheit (41 degrees Celsius). Different tabletops couldbe designed with different spacing of the heating element, therebyproviding a designed amount of heating based on the spacing of theheating element. Tabletops can also include multiple heating elements,as discussed in more detail below. The preferred heating elementincludes a foil shield, a braided copper ground plane, a hightemperature covering for the two individual elements preferably made ofEthylene tetrafluoroethylene (ETFE), with the individual elements madeof a low-oxygen copper alloy.

Variations other than the commercially-available heating cable fromProMelt referenced above can also be used. For example, while theProMelt heating cable has a polyurethane outer jacket, this outer jacketis not needed for the radiant furniture disclosed herein. Thispolyurethane outer jacket is provided in the ProMelt heating cable tomake the heating cable rugged enough to walk on after installation,which is typically done as concrete is poured over the heating cable indriveways and sidewalks. Because the heating cable in the tabletopdisclosed herein need not be walked on, the polyurethane jacket can beomitted.

FIG. 2 shows the heating element 210 is one continuous coil thatincludes several runs, with a single point A that represents an exitpoint to tabletop 110 for electrical connections connected to theheating element 210. In the most preferred implementation, an electricalcable is connected to the heating element 210 at connection points thatare embedded within the tabletop 110, with the cable passing out of thetabletop 110 at point A to be connected to a controller. In the mostpreferred implementation, heating element 210 includes two individualelements that are electrically insulated and run in parallel, and aresuitably terminated at the far end opposite the electrical connectionsby electrically connecting the two. Applying power between the twoconnections to the heating element 210 results in turning on the heatingelement 210, while removing power between the two connections results inturning off the heating element 210. The outer-most run of the heatingelement 210 is preferably spaced relatively close to the outer edge 260of the tabletop to provide effective heating right at the edge of thetabletop. In one suitable implementation, the heating element 210 isplaced at 0.5 inch (13 mm) from the outer edge 260 of the tabletop 110,or from the edge of other radiant furniture.

In the preferred implementation, the spacing between the runs of theheating element is closer together near the outer edge 260 of thetabletop 110 than it is farther towards the middle of the tabletop.Thus, a spacing 240 between the two outside runs of the heating elementis less than the spacing 250 between the second and third runs of theheating element. Thus, the outside edge of the tabletop 110 could have aspacing of the heating element that provides 90 watts per square foot(970 watts per square meter), while the spacing of the heating elementpast the first two or three runs of the heating element could have aspacing of the heating element that provides a lower wattage per squarefoot, such as 75 watts per square foot (810 watts per square meter) oreven 50 watts per square foot (540 watts per square meter). Providing ahigher density of heating element in the outer edge is desirable becausethe outer edge loses heat more quickly than the interior of the tabletop110. The higher density of heating element in the outer edge thusprovides better heating performance by providing more heat at the exactlocation where more heat is lost from the tabletop. In addition, theouter edge of the tabletop is where a person sits, so the higher densityof heating element in the outer edge provides more heat at the locationwhere the person most benefits from it. In the most preferredimplementation, the density of heating element 210 near the outer edge260 of the tabletop 110 is preferably at least 20% greater than thedensity of heating element 210 at a midpoint between the outer edge 260and the center of the table, shown in FIG. 2 as point E. Of course, thedensity of heating element 210 near the outer edge could be much morethan 20% greater. For example, the density of heating element 210 nearthe outer edge 260 could be 100% greater, or twice the density, comparedto a more interior portion like point E in FIG. 2 . Thus, the heatingelement 210 could be spaced 1.5 inches (3.8 cm) apart for the first oneor two runs, then could be spaced 3 in. (7.6 cm) apart for the moreinterior runs on the tabletop.

A temperature sensor 220 is preferably embedded in the tabletop 110 withpoint B representing an exit point for two electrical connectionsconnected to the embedded temperature sensor 220. In the most preferredimplementation, wires are connected to the temperature sensor, and thetemperature sensor and connections are all embedded within the tabletop110, with the wires exiting the tabletop 110 at point B for connectionto a controller. One suitable implementation of the temperature sensor220 is a thermistor, but any suitable temperature sensor could be used.One suitable thermistor is part number 1309007-044 manufactured by Rancoof Plain City, Ohio as part of the ETC family of electronic temperaturecontrols, which is available from AllPoints Foodservice Parts & Suppliesin Orlando, Fla. In addition, while the preferred implementation has thetemperature sensor embedded within the concrete mix of the tabletop 110,the temperature sensor could instead be thermally coupled to thetabletop 110 without being embedded within the concrete mix of thetabletop 110. Furthermore, while the temperature sensor 220 is shownnear the center of tabletop 110, it could instead be place at or nearthe outer edge 260 of tabletop 110 so it can more accurately measuretemperature near a person seated at the table. The disclosure and claimsherein expressly extend to any suitable location for the temperaturesensor 220.

FIG. 3 shows a cross-sectional view of the tabletop 110 in FIG. 2 takenalong the lines 3-3. In this specific implementation, the tabletop 110includes a reinforcing member 310, such as rebar. The reinforcing member310 is placed near the outer edge 260 of the tabletop 110 to providestrength at the outer edge 260 of the tabletop 310. Note the outer runof the heating element 210 could be both mechanically and thermallycoupled to the reinforcing member 310 to enhance the thermal transfer ofheat from the heating element 210 to the concrete mix in the tabletop110. Note the various runs of the heating element shown in FIG. 2 arerepresented in cross-section as small circles in FIG. 3 , with some ofthese labeled 210 in FIG. 3 .

A wire mesh not shown in FIG. 3 could be used in addition to or as thereinforcing member 310. The wire mesh could be a 2 inch×4 inch (5.1cm×10 cm) or in a 4 inch×4 inch (10 cm×10 cm) wire mesh. Of course,other sizes of wire mesh could also be used. In addition to giving thetabletop additional structural strength, the wire mesh provides asupport for attaching the heating element in the desired position so theheating element stays in the desired position while pouring the concretemix. For example, the heating element could be attached to the wire meshat various locations using wire ties.

The tabletop 110 preferably includes a structural support 330 embeddedin the concrete mix that provides one or more attachment points forattaching a support for the tabletop 110. The structural support 330 isshown with threaded members 320 that provide anchors for attaching thesupport 120 to the tabletop 110 using a plurality of bolts. Thestructural support 330 could be, for example, a metal bracket with metalthreaded members 320 attached to the metal bracket using bolts or welds.Once embedded in the concrete mix of the tabletop 110, the structuralsupport 330 becomes a solid anchor point for attaching the support 120to the tabletop 110.

One can appreciate from the cross-sectional view of the tabletop 110 inFIG. 3 how this tabletop 110 can be formed of a concrete mix. A circularform that has a bottom and sides can be used. A circular ring of rebaror other reinforcing member 310 could be installed near the outer edgeof the form. The heating element 210 and temperature sensor 220 can beinstalled within the form as shown in FIG. 2 . The heating element 210could be structurally and thermally coupled to the reinforcing member310 using wire zip ties, or other attachments. The heating element 210could be spaced from the bottom and sides of the form and from differentruns of itself using any suitable spacer, such as plastic spacers. Thestructural support 330 is also placed within the form, and may be spacedfrom the bottom of the form using one or more suitable spacers, such asplastic spacers. A decorative material such as aggregate or glass may beplaced at the bottom of the form. In the alternative, no decorativematerial is used. Concrete is then poured into the form, which flowsaround the heating element 210 and structural support 330 to the bottomof the form until the form is filled. A circular spacer could be used tocreate the indentions 340 shown in FIG. 3 by embedding the circularspacer into the wet concrete. The form may then be vibrated to eliminateall bubbles and voids in the concrete mix. The concrete is then left inthe form to harden. When the concrete is removed from the form, it hasthe cross-sectional appearance shown in FIG. 3 . Making the tabletop outof a concrete mix allows numerous known techniques for decorativeconcrete to be used. For example, decorative material could be placed atthe bottom of the form, which produces a tabletop with the decorativematerial on the top of the tabletop. The concrete surface of thetabletop could also be ground or stained to achieve a decorative look.Proper decorative techniques can produce tabletops that appear to bemade of granite, marble or other stone. The disclosure and claims hereinexpressly extend to any and all finishes and looks that could be put onradiant furniture.

Referring to FIG. 4 , a block diagram shows various components ofradiant furniture 400. Table 100 shown in FIGS. 1-3 is one suitableexample of radiant furniture 400. Radiant furniture 400 includes one ormore heated surfaces 410 that preferably include one or more heatingelements 420 and one or more temperature sensors 430. The radiantfurniture 400 also includes a controller 450 that includes a powerswitcher 460, controller logic 470 and a power supply 490. The powerswitcher 460 is any suitable means for applying power to the heatingelement(s) 420. One suitable implementation for power switcher 460 is arelay that selectively applies power to or removes power from theheating element(s) 420 under control of the controller logic 470.Another suitable implementation for power switcher 460 is a powertransistor. Of course, other implementations for power switcher 460 arewithin the scope of the disclosure and claims herein. The controllerlogic 470 includes one or more temperature threshold(s) 480 thatdetermine when the controller logic 470 activates the power switcher 460to apply power to the heating element(s) 420, and deactivates the powerswitcher 460 to remove power from the heating element(s) 420. The powersupply 490 preferably provides power for the controller logic 470 aswell as power routed through the power switcher 460 to the heatingelement(s) 420. The radiant furniture 400 may optionally include a knob472 or other control that allows a user to adjust the temperaturethreshold(s) 480 to vary the heat produced by the radiant furniture 400according to the user's preference. For example, in one suitableimplementation, turning the knob 472 all the way in one direction willincrease the temperature threshold(s) 470 to be four degrees warmer,while turning the knob 472 all the way in the opposite direction willdecrease the temperature threshold(s) 470 to be four degrees cooler. Ofcourse, any suitable adjustment mechanism could be used to allow a userof the radiant furniture to adjust the temperature threshold(s) 480 byany suitable amount. Suitable adjustment mechanisms include withoutlimitation knobs, push-buttons, a membrane keypad, a remote control,etc.

Controller 450 can control a single heated surface 410. Controller 450can also control multiple heated surfaces 410, either within a singlepiece of radiant furniture or across multiple pieces of radiantfurniture. FIG. 4 shows heated surface(s) 410 with heating element(s)420 and temperature sensor(s) 430 to represent that controller 450 cancontrol multiple heated surfaces in one piece of radiant furniture (suchas a picnic tabletop and bench seats) or multiple heated surfaces inmultiple pieces of radiant furniture (such as multiple tables at arestaurant).

One suitable implementation of controller 450 is commercially-availablecontroller made by Ranco of Plain City, Ohio as part numberETC-141000-000. This is a NEMA type 4X microprocessor-based electronictemperature controller. This controller allows setting the unit forFahrenheit or Celsius scale, allows setting a Setpoint Temperature(which corresponds to a temperature threshold as disclosed herein),allows for setting a differential temperature to determine at whattemperature the controller turns on power after turning off power whenthe Setpoint Temperature is reached, and allows setting the unit forcooling or heating mode. Of course, many other controllers, bothcommercially-available and custom-made, could also be used within thescope of the disclosure and claims herein.

FIG. 5 shows one suitable method 500 for the controller 400 to functionfor radiant furniture that includes one heating element, such as table100 shown in FIGS. 1-3 . The temperature sensor(s) are read (step 510).The temperature sensor(s) read in step 510 are temperature sensors 430that sense the temperature of the heated surface(s) 410. In one suitableimplementation, when multiple temperature sensors are used in a singleheated surface, the temperatures provided by the multiple temperaturesensors can be averaged to provide an average temperature between themultiple temperature sensors. When the temperature sensor senses atemperature of the heated surface 410 that is less than a definedtemperature threshold (step 520=YES), the controller turns on theheating element(s) (step 530). Turning on the heating element(s) meansthe controller activates the power switcher 460 to apply power to theheating element(s) 420. When the temperature sensor senses a temperatureof the heated surface 410 that is not less than the temperaturethreshold (step 520=NO), the controller turns off the heating element(s)(step 540). Method 500 thus turns on the heating element(s) when thetemperature of the heated surface is less than a desired thresholdtemperature, and turns off the heating element(s) when the temperatureis at or above the desired threshold temperature, thereby keeping thetemperature of the heated surface near the desired thresholdtemperature.

Radiant furniture as disclosed herein can include multiple heatingelements. The multiple heating elements can be turned on and off at thesame time. In the alternative, the multiple heating elements can beturned on and off independently. Referring to FIG. 6 , a tabletop 610represents a second embodiment for the tabletop 110 shown in FIG. 1 .The tabletop 610 includes two separate elements, a first 620 withelectrical connections that exit the tabletop 610 at point A, and asecond 630 with electrical connections that exit the tabletop at pointC. Note these two separate elements 620 and 630 are interleaved witheach other. The second heating element 630 has portions that are shownin dotted lines where it crosses the first heating element 620 to makeit clear which runs are connected together. The two heating elements 620and 630 can cross without touching when the heating elements are placedat different levels in the tabletop, as shown in FIG. 7 . The firstheating element 620 is placed at an upper position shown in FIG. 7 whilethe second heating element 630 is placed at a lower position in FIG. 7 ,thereby allowing them to cross without touching. Providing two heatingelements that can be independently turned on or off by the controllerallows greater versatility in how the tabletop 610 is used. For example,during weather that is slightly cool, turning on only the first heatingelement might provide the desired level of heating. For much colderweather, such as outside tables used at ski resorts, turning on bothheating elements might be required to achieve the desired temperature.

Multiple heating elements can have different threshold temperatures thatallow them to be independently controlled by the controller. Referringto FIG. 8 , method 800 represents functions of the controller 450 shownin FIG. 4 when driving two heating elements independently. Thetemperature sensor(s) are read (step 810). The temperature sensors readin step 810 are the temperature sensor(s) 430 that sense the temperatureof the heated surface(s) 410. When the temperature sensor senses atemperature of the heated surface(s) 410 lower than a low temperaturethreshold (step 820=YES), both heating elements are turned on (step830). When the temperature sensor(s) sense a temperature of the heatedsurface(s) 410 that is not less than the low temperature threshold (step820=NO), but sense a temperature that is between the low temperaturethreshold and a high temperature threshold (step 840=YES), only one ofthe two heating elements is turned on (step 850), while the other isturned off. When the temperature sensor senses a temperature of theheated surface(s) 410 that is not less than the low temperaturethreshold (step 820=NO) and that is not between the lower temperaturethreshold and the high temperature threshold (step 840=YES), this meansthe temperature of the heated surface(s) 410 is at or above the hightemperature threshold, so both heating elements are turned off (step860). A simple example will illustrate. Let's assume a radiant table isused as an outside table for a ski resort, where the ambient temperaturecan be very cold. Let's further assume a high temperature threshold of100 degrees Fahrenheit (38 degrees Celsius), which is the desiredtemperature for the tabletop. A low temperature threshold of 80 degreesFahrenheit (27 degrees Celsius) could be specified, so that when thetable is first warming up after being turned on, both heating elementsare turned on to bring the tabletop to 80 degrees Fahrenheit (27 degreesCelsius) as quickly as possible. Once the tabletop reaches 80 degreesFahrenheit (27 degrees Celsius), one of the two heating elements wouldbe turned off, with the remaining heating element remaining turned onuntil the tabletop reaches the 100 degrees Fahrenheit (38 degreesCelsius) desired operating temperature (upper temperature threshold).Note that on very cold days, the one heating element may be insufficientto warm the tabletop from the 80 degrees Fahrenheit (27 degrees Celsius)low temperature threshold to the 100 degrees Fahrenheit (38 degreesCelsius) upper temperature threshold. The controller logic 470 in thecontroller 450 could include programming or logic that could measuretemperature rise of the radiant furniture over time. Thus, if thetabletop achieves a temperature of 80 degrees Fahrenheit (27 degreesCelsius) in 30 minutes, but after another 30 minutes the temperature ofthe tabletop using only one heating element is only 85 degreesFahrenheit (29 degrees Celsius), the controller can recognize the oneheating element is insufficient to achieve the 100 degrees Fahrenheit(38 degrees Celsius) upper temperature threshold, and can then turn onboth heating elements until the 100 degrees Fahrenheit (38 degreesCelsius) upper temperature threshold is reached. Because the controller450 also has access to one or more ambient temperature sensors 440, thecontroller can alter its function according to ambient temperature. Forexample, the controller 450 could be programmed to turn on a singleheating element between the low temperature threshold and uppertemperature threshold when the ambient temperature is above 55 degreesFahrenheit (13 degrees Celsius), but to turn on two heading elementswhen the ambient temperature is less than 55 degrees Fahrenheit (13degrees Celsius). Of course, any suitable number of heating elements,temperature sensors, and ambient temperature sensors could be used. Forexample, four different heating elements could be used in a singleheated surface, with the controller independently driving the fourheating elements according to defined temperature thresholds. A heatedsurface 410 could include multiple temperature sensors 430, where thecontroller takes readings from the multiple temperature sensors 430 andcomputes an average temperature reading. In another variation, onecontroller 450 could control different heated surfaces that each has oneor more heating elements. For example, a picnic table could have aheated tabletop and heated bench seats, and controller 450 couldindependently control the heating elements in both benches to achieve adesired heat level for the benches, while independently controlling theheating element in the tabletop to a different temperature threshold. Inaddition, multiple controllers could be used to control different heatedsurfaces. Thus, for the example above, with a picnic table with a heatedtabletop and two heated bench seats, three different controllers couldbe used, one for the tabletop and two for the two heated bench seats.The disclosure and claims herein expressly extend to any suitable numberof controllers, heating elements and temperature sensors in radiantfurniture.

Because the controller 450 in FIG. 4 can measure the temperature ofambient air using one or more ambient temperature sensors 440, thecontroller 450 can take the ambient air temperature into account whencontrolling the heating elements in the heated surfaces. Referring toFIG. 9 , method 900 shows one suitable adjustment the controller couldmake based on ambient temperature. We assume an adjustment threshold isdefined in the controller. The ambient temperature sensor(s) are read(step 910). When the ambient temperature is less than the ambientthreshold (step 920=YES), the temperature thresholds in the controllerare adjusted (step 930). When the ambient temperature is not less thanthe ambient threshold (step 920=NO), method 900 is done. Method 900 thusillustrates a very simply way for the controller to take ambient airtemperature into account, and to vary the temperature thresholdsaccording to ambient air temperature. Thus, using the example of anoutside table at a ski resort, the controller could adjust thetemperature thresholds when the weather gets very cold to provide moreheat to the heated tabletop.

It is also within the scope of the disclosure and claims herein toprovide a heated surface where only part of the surface is heated.Referring to FIG. 10 , a tabletop 1010 represents an alternativesuitable implementation for the tabletop 110 shown in FIG. 1 . In thisimplementation, the heating element 1020 does not extend to the centerof the tabletop 1010. This allows the center of the tabletop 1010 to becooler than the outside portion that has the heating element 1020. PointA is an exit point for electrical connections to the heating element1020, and point B is an exit point for electrical connections to thetemperature sensor 220. Note the temperature sensor 220 has been movedfrom the center of the table to a position closer to the heating element1020, since the center of the table does not include any heatingelement. Thus, a person dining at an outside table on a cool eveningcould enjoy the heat of the tabletop 1020 while placing their icedbeverage towards the center of the tabletop 1010 so the heat will notwarm their drink and melt the ice in the beverage to the same extent aswould happen if the person were to place the drink on the part of thetable that includes the heating element 1020.

While electrical heating elements are discussed above, radiant furniturecould instead be made using hot water supplied hydronic tubing, wherehot water is pumped through heating tubes (water pipes) embedded in theconcrete mix of the table. Thus, heating element 210 in FIGS. 2 and 3 ,heating elements 620 and 630 in FIGS. 6 and 7 , and heating element 1020in FIG. 10 could all be replaced by suitable heating tubes that carryhot water. Note that when using heating tubes, it will be required tomake a connection to both ends of the heating tube so the hot water canflow from one end to the other. Suitable heating tubes include any typeof known pipe, including metal pipe such as copper tubing, polyvinylchloride (PVC) pipe, PEX tubing, rubber tubing such as Delta-Tube SDavailable from Delta T Solutions in San Marcos, Calif., etc. Anysuitable heating tube that is capable of carrying hot water can be used.

FIG. 11 shows another example of radiant furniture 1100 that is heatedwith hot water. The heated surface(s) 1110 include one or more heatingtube(s) 1120. The temperature sensor(s) 420 and ambient temperaturesensor(s) 440 could be the same as used in the radiant furniture 400shown in FIG. 4 . The controller 1170 uses the temperature threshold(s)480 to activate a pump 1154 that pumps hot water from a hot water supply1152 through the heating tubes 1120. The hot water supply can be anysuitable hot water supply, including a water heater with a tank, atankless water heater, a natural hot spring, or any other suitablesource of hot water. The power supply 490 and adjustment mechanism 472could be the same as used for the electric configuration shown in FIG. 4.

The hot water supply 1152 in FIG. 11 could also be replaced orsupplemented with a cold water supply to cool the radiant furniture,when needed. Thus, in very hot climates, cold water could be circulatedfrom a cold water supply by the pump 1154 through the heating tubes 1120to cool the heated surface(s) 1110.

FIG. 12 shows another embodiment for radiant furniture 1200 within thescope of the disclosure and claims herein. Heated furniture 1200comprises a controller 1210 coupled to one or more heated surfaces 1232and one or more ambient temperature sensors 1254 in an ambientenvironment 1252. A heating element power supply 1220 is a suitablepower supply for powering one or more heating elements 1234 in one ormore heated surfaces 1232. In one suitable implementation, the heatingelement power supply 1220 is an alternating current (AC) power supply,such as a 120 VAC or 240 VAC supply from a wall receptacle. A heatingelement interface 1230 receives a control signal asserted by controllerlogic 1240, and in response, connects the heating element power supply1220 to the heating element(s) 1234. When the control signal from thecontrol logic 1240 to the heating element interface 1230 is notasserted, the heating element interface 1230 does not connect theheating element power supply 1220 to the heating element(s) 1234. Theheating element interface can be any suitable electrically-controlledswitch, including without limitation a relay, a power transistor, etc.

The controller 1210 includes a heated surface sensor interface 1270 thatreceives input from one or more temperature sensor(s) 1236 in the heatedsurface(s) 1232 and provides that input to the controller logic 1240.One suitable example for temperature sensor(s) 1236 are thermistors thatchange resistance as their temperature changes. Another suitable examplefor temperature sensor(s) 1236 are digital temperature sensors thatreport temperature in a digital form. Of course, other suitableimplementations for the temperature sensor(s) 1236 are within the scopeof the disclosure and claims herein. In one suitable embodiment, theheated surface interface 1270 can pass a signal from the temperaturesensor(s) 1236 directly to the controller logic 1240. In a differentsuitable embodiment, the heated sensor interface 1270 can convert thesignal from the temperature sensor(s) 1236 into a different form thatcan be read by the controller logic 1240. For example, the heatedsurface sensor interface 1270 could convert a voltage value across athermistor-type temperature sensor into a digital value that representsto the controller logic 1240 the temperature of the temperature sensor.

The ambient sensor interface 1280 receives input from one or moreambient temperature sensors 1254 in an ambient environment 1252. Theambient environment 1252 can be air or could be a solid surface that isseparate from the heated surface(s) 1232. As discussed above withrespect to temperature sensor 1236, the ambient temperature sensor 1254could be a thermistor, a digital temperature sensor that reportstemperature in a digital form, or any other suitable temperature sensorthat can report temperature to the controller 1210. In one specificembodiment, the ambient temperature sensor 1254 is a thermistor thatextends to an exterior of an enclosure for the controller 1210 so it canmeasure the temperature of the air away from the heated surface(s) 1232and outside of the enclosure for the controller 1210. In anotherspecific embodiment, the ambient temperature sensor could be attached toa surface that is not part of the heated surface, such as a table leg.The ambient environment 1252 can be any suitable environment thatprovides a temperature reading from the ambient temperature sensor(s)1254 that informs the controller 1210 of the ambient temperature of theambient environment 1252, which is separate from the heated surface(s)1232. The ambient sensor interface 1280, like the heated surface sensorinterface 1270 discussed above, can provide the signals from the ambienttemperature sensor(s) 1254 directly to the controller logic 1240, orcould convert the signals from the ambient temperature sensors 1254 toany suitable form that can be read by the controller logic 1240.

Controller logic 1240 is coupled to a controller power supply 1260,which can be any suitable power supply, including without limitation analternating current (AC) power supply, a direct current (DC) powersupply, batteries, a solar panel, etc. Controller 1210 also includes amode selection circuit 1290 that tells the controller logic 1240 themode selection when the controller logic 1240 powers on. The modeselection circuit 1290 can be any suitable way to represent differentmodes to the controller logic 1240. Specific examples include dualinline package (DIP) switches and connector pins that receive jumpers.Of course, other implementations of a mode selection circuit arepossible, including a resistive knob, a digital knob, a keypad, etc. Themode selection circuit 1290 expressly extends to any suitable circuitthat is capable of communicating the selection of different modes to thecontroller logic 1240, including one or more operating modes and acalibration mode, as discussed in more detail below.

Controller logic 1240 receives input from a knob 1242 that is preferablymounted to an enclosure for the controller 1210 such that the knob 1242is external to the enclosure and can be turned by a person using his orher fingers. The knob 1242 can include any suitable circuitry forcommunicating different positions of the knob, including a resistivepotentiometer and a digital knob that provides a different digital valuefor each of a plurality of positions of the knob. The controller logic1240 receives input from the knob 1242, and performs different functionsdepending on the knob position, as explained in more detail below.

One suitable implementation for the knob 1242 in FIG. 12 is shown inFIG. 13 . Knob 1242 is a resistive potentiometer in a voltage dividercircuit that provides a voltage that is proportional to the knobposition. The knob includes a white mark that indicates the positionselected by the knob, as shown pointing to the AUTO position 1320 inFIG. 13 . The knob 1242 preferably includes a detente center positioncorresponding to AUTO 1320 in FIG. 13 , and can be turnedcounter-clockwise until the knob 1242 reaches the OFF position 1310 andcan be turned clockwise until the knob 1242 reaches the ON position1330. The function of the controller logic 1240 depends on the modeselection circuit 1290 and the position of the knob 1242, as discussedin detail below.

The controller logic 1240 can include any suitable hardware orcombination of hardware and software that provides the functionsdisclosed herein. One suitable implementation for controller logic 1240is a microcontroller that includes programming to perform the functionsdisclosed herein. Other implementations are also possible, including amicroprocessor, a state machine, etc.

The controller logic 1240 in FIG. 12 preferably includes a table ofambient temperatures and corresponding temperature thresholds 1250. Onesuitable implementation for the table of ambient temperatures andcorresponding temperature thresholds 1250 is shown in table 1400 in FIG.14 . All temperatures in FIG. 14 are in degrees Fahrenheit, followed bydegrees Celsius in parentheses. The table 1400 includes temperaturethresholds for a table, for a seating panel with no pad, and for aseating panel with a pad. When the knob is in the ON position, thecorresponding default temperatures for a table, seating panel with nopad, and seating panel with pad are 105 degrees Fahrenheit (41 degreesCelsius), 100 degrees Fahrenheit (38 degrees Celsius), and 110 degreesFahrenheit (43 degrees Celsius), respectively. When the knob is in theOFF position, the controller logic does not power the heating elements.When the knob is between the ON and OFF positions, the temperaturethreshold used by the controller depends on the type of heated surfaceas specified by the mode selection circuit 1290 in FIG. 12 and theambient temperature. A few simple examples will illustrate. If the modeselection circuit 1290 is set to “Table”, and if the ambient temperatureis 66 degrees Fahrenheit (19 degrees Celsius), the correspondingtemperature threshold is 102 degrees Fahrenheit (39 degrees Celsius). Ifthe mode selection circuit is set to “Seating/No Pad”, and the ambienttemperature is 78 degrees Fahrenheit (26 degrees Celsius), thecorresponding temperature threshold is 81 degrees Fahrenheit (21 degreesCelsius). If the mode selection circuit is set to “Seating/With Pad”,and the ambient temperature is 60 degrees Fahrenheit (16 degreesCelsius), the corresponding temperature threshold is 106 degreesFahrenheit (41 degrees Celsius). The goal of the radiant furniture is toprovide a level of heating that is comfortable for people. The amount ofheating needed varies depending on the ambient temperature and the typeof furniture, as shown in the table 1400 in FIG. 14 . In general, as theambient temperature decreases, the temperature threshold increases, andas the ambient temperature increases, the temperature thresholddecreases. The ability to dynamically change the temperature thresholdaccording to ambient temperature is a significant advantage not known inthe art.

The controller 1210 also includes a temperature correction value 1292that is determined during a calibration of the controller 1210.Referring to FIG. 15 , a method 1500 represents steps performed tocalibrate the controller 1210 in FIG. 12 . The controller is powered off(step 1510). The mode selection circuit is set to calibrate and is alsoset to select the type of heated surface being controlled by thecontroller (step 1520). The controller knob is set to the center AUTOposition 1320 shown in FIG. 13 (step 1530). The controller is thenpowered on (step 1540). The controller heats the heated surface to theDefault (ON) temperature for the selected heated surface type (step1550). Some time is allowed to pass for the heated surface to heat tothe default (ON) temperature (step 1560). The temperature of the heatedsurface is them measured at several locations to determine a hot spot(step 1570). The measurement of the hot spot in step 1570 can be doneusing any suitable temperature measurement apparatus. The preferredinstrument for measuring the hot spot in step 1570 is a heat camera,which visually identifies hot spots using colors. Of course, otherinstruments could also be used, such as a hand-held pyrometer, such aslaser temperature gauges that are readily available. Such instrumentsare generally referred to herein as temperature measurement instrumentsthat are external to the controller. When the temperature of the hotspot is greater than the default temperature (step 1580=YES), the knob1242 in FIG. 13 is turned counter-clockwise (CCW) until the temperatureof the hot spot equals the default temperature (step 1582). Note sometime will need to pass in step 1582 to see the changed temperatureequalize in the heated surface. Let's assume for an example that thehotspot is five degrees Fahrenheit (3 degrees Celsius) above the defaulttemperature. The knob 1242 in FIG. 13 is turned CCW to the −5 setting,and some time passes to let the changed temperature setting take effect.Assuming the temperature of the hot spot settles to the defaulttemperature with the knob in the −5 degree setting, the temperaturecorrection value of −5 degrees Fahrenheit (−3 degrees Celsius) iswritten to the temperature correction value 1292 in a non-volatilememory in the controller 1210 (step 1594). The controller is thenpowered off (step 1596). The controller is then ready to heat the heatedsurface in the radiant furniture.

When the temperature of the hot spot is not greater than the defaulttemperature (step 1580=NO), and when the temperature of the hot spot isnot less than the default temperature (step 1590=NO), this means the hotspot is at the default temperature. In this case, the temperaturecorrection value of zero is written to the non-volatile memory (step1594), and the controller is powered off (step 1596). The controller isthen ready to heat the heated surface.

When the temperature of the hot spot is not greater than the defaulttemperature (step 1580=NO) but the temperature of the hot spot is lessthan the default temperature (step 1590=YES), the knob is turnedclockwise (CW) until the temperature of the hot spot is equal to thedefault temperature (step 1592). The temperature correction value isthen written to the non-volatile memory (step 1594), the controller ispowered off (step 1596). The controller is then ready to heat the heatedsurface.

Note there may be some fine tuning in steps 1582 and 1592 in FIG. 15 .For example, if the knob is turned in step 1582 or step 1592 and the hotspot does not equal the default temperature, the knob may be turnedagain, and this process is repeated until the temperature of the hotspot is equal to the default temperature.

The calibration mode is useful due to variations in manufacturingprocesses and materials, and due to different configurations of heatedsurfaces. The calibration mode allows adjusting the controller tocontrol a number of different configurations and types of radiantfurniture.

Once the controller has been calibrated and the temperature correctionvalue has been written to the non-volatile memory in the controller, thecontroller is ready to heat radiant furniture that includes a heatedsurface. Referring to FIG. 16 , a method 1600 begins by powering off thecontroller (step 1610). The mode selection circuit is set to the type ofheated surface (step 1620). The type of heated surface was previouslyselected during the calibration mode represented in FIG. 15 , so themode selection circuit could be changed simply to remove the calibrationsetting while maintaining the type of heated surface setting. A simpleexample will illustrate. Let's assume the mode selection includes aconnector header with four sets of two parallel pins, with each of thefirst three sets of parallel pins setting the type of heated surfacewhile the fourth set of parallel pins is used for calibration mode. Inthis example, one jumper is placed on one of the three sets of parallelpins to select the type of heated surface, and another jumper is placedon the fourth set of parallel pins to select calibration mode. In thisexample, setting the mode selection circuit to the type of heatedsurface in step 1620 immediately following calibration would mean simplyremoving the calibration jumper and leaving the jumper for the type ofheating surface in place.

Once the mode selection circuit is set to the type of heated surface instep 1620, the controller is powered on (step 1630). On power on, thecontroller reads the mode selection circuit to determine the type ofradiant furniture being heated. The temperature correction value is alsoread from non-volatile memory (step 1640). When the knob is in the OFFposition 1310 in FIG. 13 (step 1650=YES), the controller does not applyany power to the heated surface (step 1652). When the knob is not in theOFF position 1310 (step 1650=NO), but the knob is in the ON position1330 in FIG. 13 (step 1660=YES), the desired temperature is set to thedefault temperature adjusted by the temperature correction value (step1662). A default temperature setting is needed, especially when theheated furniture is being displayed for sale in a furniture showroom.When the ambient temperature is 74 degrees Fahrenheit (23 degreesCelsius), for example, the target temperature threshold in table 1400for a table is 94 degrees Fahrenheit (34 degrees Celsius). This 20degree Fahrenheit (11 degrees Celsius) differential from 74 degreeFahrenheit (23 degrees Celsius) ambient to 94 degree Fahrenheit (34degrees Celsius) table is not nearly as noticeable to a person who putshis or her hand on a heated tabletop as the 31 degree Fahrenheit (18degrees Celsius) differential from 74 degree Fahrenheit (23 degreesCelsius) ambient to 105 degree Fahrenheit (41 degrees Celsius) defaulttemperature. The ON position for 1330 can thus be used as a “demo mode”for the radiant furniture, setting the target temperature thresholdhigher than normal to allow a person to more easily feel the warmthcoming from the radiant furniture.

When the knob is between the OFF position 1310 and ON position 1330(step 1650=NO and 1660=NO), this is the normal operating mode for thecontroller to heat the radiant furniture. The ambient temperature isread from the ambient temperature sensor (step 1670). The targettemperature for the heated surface for this ambient temperature isdetermined from the temperature table (step 1672). When the knob is inthe AUTO position 1320 in FIG. 13 (step 1680=YES), the desiredtemperature is set to the target temperature adjusted by the temperaturecorrection value (step 1682). When the knob is not in the AUTO position1320 (step 1680=NO), the desired temperature is set to the targettemperature adjusted by the temperature correction value and the valueon the knob (step 1690). Method 1600 is then done.

A few simple examples will illustrate. We assume for these examples thecalibration in FIG. 15 has already been performed, and a temperaturecorrection value of −3 degrees Fahrenheit (−2 degrees Celsius) has beenstored in the non-volatile memory of the controller in step 1594 in FIG.15 . We further assume the heated surface is a table. When the knob isin the ON position 1310 in FIG. 13 (step 1660=YES), the desiredtemperature is set to the default temperature, which from the table 1400is 105 degrees Fahrenheit (41 degrees Celsius) when the heated surfaceis a table, adjusted by the temperature correction value of −3 degreesFahrenheit (−2 degrees Celsius), which means the desired temperature isset to 102 degrees Fahrenheit (39 degrees Celsius). We now assume theknob is in the +5 degree position shown in FIG. 13 . The knob is not inthe OFF position (step 1650=NO) and is not in the ON position (step1660=NO), so the ambient temperature is read from the ambienttemperature sensor (step 1670). We assume the ambient temperature readin step 1670 is 65 degrees Fahrenheit (18 degrees Celsius). Method 1600then consults the temperature table and determines the targettemperature for a table at 65 degrees Fahrenheit (18 degrees Celsius) is103 degrees Fahrenheit (39 degrees Celsius), as shown in FIG. 14 . Theknob is not in the AUTO position (step 1680=NO) because the knob is setto +5 degrees. The desired temperature is then set as the targettemperature of adjusted by the temperature correction value and thevalue on the knob, meaning the desired temperature is set to103+(−3)+5=105 degrees Fahrenheit (41 degrees Celsius). Method 1600illustrates how the desired temperature can be adjusted for both thetemperature correction value determined during calibration of a heatedsurface and the value on the knob. Note the “desired temperature” in thediscussion above with respect to FIG. 16 is a temperature threshold inthe controller, below which the controller turns on the heatingelement(s) in the heated surface and above which the controller turnsoff the heating element(s) in the heated surface, as shown in FIG. 5 anddiscussed above.

The knob on the controller gives a user the option of increasing ordecreasing the temperature of the table to suit the user's preference.If the user likes more heat than the radiant furniture provides with theknob in the AUTO position, the user can turn the knob clockwise toincrease the temperature from one to 10 degrees Fahrenheit (one to 6degrees Celsius). If the user likes less heat than the radiant furnitureprovides with the knob in the AUTO position, the user can turn the knobcounter-clockwise to reduce the temperature from one to 10 degreesFahrenheit (one to 6 degrees Celsius). The knob thus gives the user thecapability of adjusting the level of heat in radiant furniture to theuser's liking.

FIG. 10 shows one suitable embodiment for a round heated table thatincludes heating in the outer portion of the table and does not includeany heating on an inner portion of the table, as shown by the runs ofthe heating element in FIG. 10 . Providing an inner portion of the tablethat is not heated creates an inner area where a person sitting at thetable can place drinks or other things the person does not want on theheated surface. Tests by applicant have shown the temperaturedifferential between the heated portion of the table and the unheatedportion of the table such as the one in FIG. 10 can be considerable. Thegreater the difference in temperature between the inner, unheatedportion and the outer, heated portion, the greater the thermal stress inthe concrete tabletop. This thermal stress can create cracks in thetable for a normal concrete mix. To avoid cracking in the tabletop dueto thermal stress, an improved concrete mix can be used. One suitableconcrete mix that can withstand significant thermal stress withoutcracking is ElastoCrete manufactured by ElastoCrete LLC in St. George,Utah. Other ingredients could also be added to concrete to reduce thelikelihood of cracking due to thermal stress. For example, siloxane invarious forms could be used to increase the flexibility and reduce therigidity of the concrete, making the concrete less likely to crack. Thedisclosure and claims herein expressly extend to using any suitableconcrete mix, including those that include ingredients that make theconcrete mix more flexible and less likely to crack.

A first suitable concrete mix for a concrete substrate for a heatedsurface in radiant furniture that uses ElastoCrete is:

50 lb (23 kg) ElastoCrete Kit (includes jugs of liquid and bags ofpowder that are mixed together) calcium carbonate powder/granulesThe size of the calcium carbonate powder/granules is preferably in therange of 0.001 inch (0.03 mm) to 0.25 inch (6.4 mm), is more preferablyin the range of 0.002 inch (0.05 mm) to 0.0625 inch (1.6 mm), and ismost preferably in the range of 0.003 inch (0.08 mm) to 0.016 inch (0.41mm). Of course, a mixture of different particle sizes can be used. Forexample, a product called Marble Pro from ACS International is onesuitable example of calcium carbonate powder that could be used in themix above. The specifications for Marble Pro state <1% for 40 mesh(0.016 inch or 0.41 mm) retained, and 50-65% for 200 mesh (0.003 inch or0.08 mm) retained. The calcium carbonate powder is preferably in therange from 20-54 lb (9 to 24 kg), more preferably is in the range of23-45 lb (10-20 kg), and most preferably in the range of 25-38 lb (11 to17 kg).

Adjustments to the weight of calcium carbonate can be made according tothe size of the powder/granules used. Smaller sizes will typicallyabsorb more liquid per weight, which means the smaller the size, theless amount of powder/granules that has to be used.

A second suitable concrete mix for a concrete substrate for a heatedsurface in radiant furniture that uses ElastoCrete is:

50 lb (23 kg) ElastoCrete Kit (includes jugs of liquid and bags ofpowder that are mixed together)silica sandIn the most preferred implementation, the silica sand includes granulesthat have different sizes over a wide range. The silica sand in the mixabove has a granule size that is preferably smaller than 0.075 inch (1.9mm), and is more preferably smaller than 0.05 inch (1.3 mm). The amountof silica sand in the mix above is preferably 0 to 18.5 lb (0 to 8.4kg), is more preferably 5 to 12 lb (2.3 to 5.4 kg), and is mostpreferably 6.5 to 7.5 lb (2.9 to 3.4 kg).

Other admixtures can be added to the concrete mix. For example, dyes,powdered colorants, and fibers may be added within the scope of thedisclosure and claims herein. A third suitable concrete mix for aconcrete substrate for a heated surface in radiant furniture is:

40% Proprietary mix (mixed 66% liquid to 34% powder by weight)45% calcium carbonate aggregates/powders15% silica sand0.2-2% dyes or colorants0.15-0.50% fibersThe proprietary mix above could be ElastoCrete, or anothersiloxane-based concrete mix that includes a liquid polymer modifiedcement blend and a powder blend that activates with the liquid. Thecalcium carbonate can be any suitable particle size. The silica sand canbe any suitable particle size. The dyes or colorants, when used, can beliquid or powder form. The fibers can be any fiber type that is suitablefor providing strength in concrete, including without limitations glassfibers, polyvinyl alcohol (PVA) glass fibers, carbon fibers, and naturalfibers, including plant-based fibers and animal-based fibers such asanimal hair, etc. When dyes/colorants and/or fibers are used, the amountof calcium carbonate aggregates/powders or sand can be reduced toprovide a desired percentage of dyes/colorants and/or fibers.

Using a concrete mix that includes ElastoCrete or siloxane increasesflexibility and therefore reduces the likelihood of the concretesubstrate cracking, this comes at a cost of the surface of the concretesubstrate being more susceptible to scratches. One way to make theconcrete substrate less susceptible to scratches is to coat the top ofthe concrete substrate with a suitable clear coat. One particularexample of a suitable clear coat that is very durable is Hydrowix soldby ElastoCrete, LLC. Of course, any suitable clear coat could be used.Adding a ground glass powder to the clear coat increases the hardness,and therefore susceptibility to scratches, in the clear coat.

Standard concrete mixes have a flexural strength that is typically10-13% of the compressive strength of the concrete. Thus, a concrete mixthat has a compressive strength of 7,000 psi (492 kg per square cm)might have a flexural strength of 700 psi (49.2 kg per square cm).Increasing flexural strength in standard concrete mixes would typicallyrequire increasing the compressive strength. Yet improved mixes providean increase in flexural strength that is much greater than what ispossible using standard concrete mixes.

Flexural strength of a concrete mix relates to the likelihood a concretesubstrate made with the mix will crack due to thermal stress. By addingingredients to a concrete mix that increases its flexural strength, thelikelihood of a heated surface cracking is reduced. This is a majorbenefit of using the ElastoCrete or siloxane in the concrete mix asdisclosed herein. ElastoCrete has a flexural strength of 2,200 psi (155kg per square cm) and has a compressive strength of 7,500 psi (527 kgper square cm). The flexural strength of ElastoCrete is thus in excessof 29% of its compressive strength, significantly higher than the 10-13%of standard concrete mixes.

Another suitable concrete mix for a heated surface is glass fiberreinforced concrete (GFRC). GFRC can have a flexural strength up to3,000 psi (211 kg per square cm) with internal reinforcements, such asrebar or wire mesh. GFRC has the additional benefit of needing lessthickness to achieve a desired flexural strength, thereby reducing thequantity of concrete mix needed and decreasing the thickness of theheated surface. One suitable GFRC mix for a concrete substrate for aheated surface in radiant furniture is:

1 part Portland cement1 part sandPozzolan at 10 to 25% cement replacementAcrylic polymer emulsion at 5% acrylic solids by weight of cementChopped alkali-resistant (AR) glass fibers at 2-6% by weightOptional admixtures: superplasticizer, color (dry or liquid)While the specific amounts and ranges above provide a suitable GFRC mixaccording to a first embodiment, the amounts could vary within the scopeof the disclosure and claims herein. For example, the amounts specifiedabove could vary by as much as 50% in a second embodiment, and morepreferably could vary by 25% in a third embodiment. The disclosure andclaims herein expressly extend to any suitable GFRC mix for a concretesubstrate in a heated surface in radiant furniture.

Another way to reduce the likelihood of a tabletop cracking is to heatthe interior portion to a lesser degree than the outer portion.Referring to FIG. 17 , a round tabletop 1710 includes an outer ringportion A that has a much higher density of heating element runs thanthe inner circular portion B. Building tables with varying layouts ofheating element runs has shown the configuration in FIG. 17 to provideeven heat in the outer portion A while providing significantly less heatin the inner portion B, thereby reducing the thermal stress in thetabletop due to temperature differential between the inner portion B andthe outer portion A. In the specific configuration shown in FIG. 17 ,the outer run of the heating element is 0.75 inches (1.9 cm) from thecenter of the heating element to the edge of the table. The second runis 1.00 inches (2.5 cm) from the center of the first run to the centerof the second run. The third run is 1.25 inches (3.2 cm) from the centerof the second run to the center of the third run. The fourth run is 2.50inches (6.4 cm) from the center of the third run to the center of thefourth run. The fifth run is 1.25 inches (3.2 cm) from the center of thefourth run to the center of the fifth run. The sixth run is 1.00 inches(2.5 cm) from the center of the fifth run to the center of the sixthrun. We thus see a pattern on the outer portion A, where the density ofthe heating element is greater at both the inside and outside edges ofthe outer portion A, while being less dense in the middle of outerportion A. Testing has shown the configuration of the heating element inFIG. 17 provides even heat in the outer portion A, and provides muchless heat in the inner portion B, yet enough to significantly reduce thethermal difference, and hence thermal stress, between the inner portionA and the outer portion B. Of course, the spacing of the runs of theheating element could vary within the scope of the disclosure and claimsherein.

The heating elements shown in FIGS. 2, 6 and 10 include two conductorsand have only one end connected to electrical power, where two wires areconnected to the two conductors on one end of the heating element (suchas at point A in FIGS. 2, 6 and 10 ), and the two conductors areterminated at the far end by electrically connecting the two conductorstogether. The heating elements shown in FIGS. 17-22 are single-conductorheating elements, and therefor require a connection at both ends of theheating element. Thus, heating element 1720 in FIG. 17 includes a firstend with a first termination 1750 that provides an electrical transitionbetween the heating element 1720 and a wire 1760 that connects to thecontroller, and a second end with a second termination 1770 thatprovides an electrical transition between the heating element 1720 and awire 1780 that connects to the controller. One suitable single-conductorheating element is a heating element manufactured by Heatizon Systems inMurray, Utah, which can make heating elements (or cables) to a specifiedlength with the needed terminations to wire that can be hooked up to apower source. An example of a suitable heating element is HeatizonSystems part number S-0.6-120V-42F-4.86, which has a length of 41.17 ft(12.55 meters). Other similar heating elements can be made in longer orshorter lengths according to the configuration of the heated surface inradiant furniture and the desired density of the heating element runs.

The heating element 1720 in FIG. 17 makes many runs in the tabletop, andin the most preferred configuration, the heating element 1720 does notoverlap itself. Overlapping the heating element would cause a hot spotin the tabletop 1710, and is therefore undesirable in the most preferredimplementation. Of course, other implementations are possible where theheating element overlaps within the scope of the disclosure and claimsherein. The configuration shown in FIG. 17 allows the wires 1760 and1780 on both ends of the heating element to exit at the same exit point,shown in FIG. 17 at 1790. The tabletop includes a temperature sensor1730 that has a connected wire 1740 that also exits the exit point 1790.When the wire 1740 for the temperature sensor 1730 crosses the heatingelements, as shown in two places in FIG. 17 , the wire is mostpreferably 0.25 inches (0.6 cm) or more separated from the heatingelement to reduce the likelihood of the heat from the heating elementdamaging the wire 1740 from the temperature sensor 1730.

The outer portion A preferably includes an outer perimeter defined bythe outer edge of the tabletop 1710 and an inner perimeter defined bythe outer edge of the inner portion B. The outer portion A has a densityof heating element runs that is much higher near the inner perimeter andouter perimeter than halfway between the inner perimeter and outerperimeter. The temperature sensor 1730 in FIG. 17 is shown approximatelyhalf the distance between the outer perimeter and the inner perimeter ofthe outer region A. Thus, we see from FIG. 17 the density of the heatingelement runs on both sides of the temperature sensor 1730 is greaterthan the density of heating element runs at the halfway point where thetemperature sensor is located. This is visually apparent in FIG. 17 bythe larger gap between the three runs closest to the outer perimeter ofthe outer region A and the three runs closest to the inner perimeter ofthe outer region A.

Heating in the tabletop 1710 in FIG. 17 can be specified in watts persquare foot (or watts per square meter). Because the density of the runsof the heating element is greater at the outside edge and near theboundary between the outer region A and the inner region B in FIG. 17than the density between these runs, the heat density at the outer edgeand near the boundary between the outer region A and the inner region Bin FIG. 17 has a heat density in watts per square foot (or watts permeter) that is most preferably at least 20% greater than the heatdensity at the midway point in the outer region A, represented in FIG.17 by the location of the temperature sensor 1730. The heat density inthe outer region A is most preferably at least 30% greater than the heatdensity in the inner region B in FIG. 17 .

The tabletop 1810 shown in FIG. 18 has a very similar configuration ofheating element runs in the outer portion A, but does not have anyconcrete material in inner portion B. Tests have shown that the heatneeded to make a person comfortable is in the outer portion A. By notpouring the concrete mix in the inner portion B, some advantages arerealized. Less of the concrete mix is used, reducing cost. The tabletop1710 is lighter. The center portion B can be filled with a decorativetop that adds to the aesthetic appearance of the tabletop, such as astained wood surface. Of course, suitable synthetic materials could alsobe used to fill in the inner portion B. When the material put in theinner portion B is thermally insulating, such as wood or plastic, heatfrom the outer portion A only minimally transfers to the material in theinner portion B. This allows cool foods such as salads and drinks to beplaced on the material in the inner portion B so they are not adverselyaffected by the heat in the outer region A. In the most preferredimplementation, the inner perimeter of the outer portion A includes alip that is formed when pouring the tabletop such that a decorativepiece can be cut to the circular dimension B shown in FIG. 18 with asuitable thickness that will allow the piece to be placed inside theinner portion B, resting on the lip in the tabletop such that the top ofthe piece is level with the concrete top in the outer portion A.

Testing with various configurations of heating elements has shown thatplacing the runs of the heating element closer together at both theinside and outside edges of the outer portion A, and placing the runsfarther apart in the middle of the outer portion A, as shown in FIG. 18, results in more even heat distribution in the outer portion A. Thus,the three runs closest to the outside edge and the three runs closest tothe inside edge have similar spacing, starting with the first run beingclose to the edge, the second run being a little farther from the firstrun, and the third run being a little farther from the second run, asshown by the dimensions in FIG. 17 . Note, however, the spacing betweenthese two sets of runs is farther apart. The wider space between the twosets of runs avoids hot spots on the tabletop. Stated generally, theheating element is spaced closer to edges and farther in the middle. Thetemperature sensor 1830 embedded in the tabletop 1810 is preferablylocated near the center of the outer portion A between the two widestruns of the heating element, as shown in FIG. 18 .

While tabletop 1810 in FIG. 18 is discussed above as a table that doesnot have an inner portion B, and thus provides both an outside and aninside perimeter to the outer portion A, it is equally within the scopeof the disclosure and claims herein to provide a tabletop 1810 where theinner portion B is the same concrete mix as the outer portion A, butwithout any heating element runs. When this is the case, the innerportion B in FIG. 18 is a representation of the part of the tabletop1810 that does not include any heating element runs. Outer portion A isstill represented by the space between the outer edge of the table andinner portion B, but inner portion B designates a region that does notinclude heating element runs, rather than designating a portion thatdoes not have any concrete mix.

A rectangular tabletop is shown at 1910 in FIG. 19 , which includes anouter portion C and an inner portion D, similar to the outer portion Aand the inner portion B shown in FIGS. 17 and 18 . The heating element1920 includes multiple runs that are most preferably configured so theydo not cross each other. The spacing of the runs from the outer edge ofthe tabletop 1910 is similar in spacing to the spacing of the runs shownin FIG. 17 . The two ends of the heating element include terminations1950 that provide wires that exit the tabletop at exit point 1990. Atemperature sensor 1930 is connected to a wire 1940 that crosses fourruns of the heating element and exits at the exit point 1990, as shownin FIG. 19 . As discussed above with reference to FIG. 17 , the wire1940 for the temperature sensor 1930 is preferably placed so it is nocloser than 0.25 inches (0.6 cm) from the heating element at thecrossing points between wire 1940 and the runs of the heating element.The density of the heating element runs in the inner portion D issignificantly less than the density of the heating element runs in theouter portion C, thereby providing significant less heating in the innerportion D, but still providing some heating to reduce the thermaldifference between the outer portion C and the inner portion D, therebyreducing the likelihood of cracks in the tabletop caused by thermalstress.

A tabletop 2010 is shown in FIG. 20 that has heating element runs in theouter portion C very similar to those shown in FIG. 19 . However,tabletop 2010 includes the inner portion D that does not have anyconcrete mix or heating elements. This allows a decorative material suchas wood or plastic to be placed within the center portion D, thusproviding a very attractive tabletop. The arrangement of the runs of theheating element in FIG. 20 is similar in many ways to the arrangement ofthe runs in FIG. 18 . Both the outer and inner edges of the outerportion C have runs that start close to the edge and are spaced atincreasing distances from each other for the first three runs, with alarger gap separating the inner set of three runs from the outer set ofthree runs. The temperature sensor 2030 is in a different position thanthe temperature sensor 1930 in FIG. 19 because the tabletop 2010 has adifferent exit point for the heating element wires and the wire 2040 forthe temperature sensor 2030. The wire 2040 only crosses two heatingelement runs as shown in FIG. 20 before arriving at the exit point. Asdiscussed above, at the point the wire 2040 crosses the heating elementruns, the distance between the wire 2040 and the heating element runs ispreferably 0.25 inches (0.6 cm) or greater.

While tabletop 2010 in FIG. 20 is discussed above as a table that doesnot have an inner portion D, and thus provides both an outside and aninside perimeter to the outer portion C, it is equally within the scopeof the disclosure and claims herein to provide a tabletop 2010 where theinner portion D is the same concrete mix as the outer portion C, butwithout any heating element runs. When this is the case, the innerportion D in FIG. 20 is a representation of the part of the tabletop2010 that does not include any heating element runs. Outer portion C isstill represented by the space between the outer edge of the table andinner portion D, but inner portion D designates a region that does notinclude heating element runs, rather than designating a portion thatdoes not have any concrete mix.

The heated tabletops shown in FIGS. 17 and 19 include a heat densitythat is greater in the outer portion than in the inner portion. In themost preferred implementation, the heat density in the outer portion Ain FIG. 17 and in the outer portion C in FIG. 19 is at least 30% greaterthan the heat density in the inner portions B and D, respectively.

In addition to heated tabletops, the radiant furniture can also includeradiant seating panels that can be used on benches, couches, chairs,etc. Two specific configurations of radiant seating panels are shown at2110 in FIGS. 21 and 2210 in FIG. 22 . The radiant panel 2110 in FIG. 21has a heating element 2120 in evenly-spaced runs that have terminations2150 that transition to wires that exit the exit point 2160. The radiantpanel 2110 could be used, for example, in a bench or couch. The radiantseating panel 2110 includes a temperature sensor 2130 that is placedbetween two of the runs of the heating element, and has a wire 2132 thatis routed to the exit point 2160. Once again, the spacing between thewire 2132 and the heating element 2120 at the point the two cross ispreferably 0.25 inches (0.6 cm) or greater.

An alternative configuration for a heated seating panel is shown at 2210in FIG. 22 . In one specific embodiment, the spacing of the outer runsin the radiant seating panel 2210 is similar to or the same as thespacing of the outer runs in the tabletop 1910 shown in FIG. 19 . Thisprovides three sets of runs on the bottom edge in FIG. 22 that have anincreasing spacing from the edge and from each other, and threecorresponding sets of runs on the top edge in FIG. 22 , with the twosets of three runs separated by runs that have a larger spacing.

The radiant seating panels 2110 in FIGS. 21 and 2210 in FIG. 22 could beused for a bench that has no back, and thus allows people to sit on bothsides of the bench. A radiant seating panel within the scope of thedisclosure and claims herein can have any suitable size, shape, andconfiguration of heating element runs. For example, a bench in the shapeof an arch could include a radiant heating panel in the correspondingshape of the arch. A sectional outdoor couch could include an L-shapedradiant seating panel that spans the different components of thesectional couch. A heated seating panel could be configured to cap ahalf-wall, thereby providing heated seating to those who sit on the halfwall. These and other examples are within the scope of the disclosureand claims herein.

Note the heated seating panels 2110 in FIGS. 21 and 2210 in FIG. 22 havedifferent densities of runs of the heating element, which results indifferent heat densities. Heated seating panel 2110 could represent anexterior bench, such as at a bus stop, where the temperature need not behigh but needs to be high enough to melt show and ice that mightotherwise accumulate on the bench. Heated seating panel 2210 couldrepresent a heated seating panel in a padded couch. The disclosure andclaims herein expressly extend to any suitable density of runs of one ormore heating elements in a heated seating panel.

Heated seating panels allow constructing both unpadded and paddedradiant furniture. Unpadded furniture can include any suitable bench orother heated seating surface that does not have anything on top, so theheat from the radiant seating panel is transferred directly to theperson who sits on the radiant heating panel. Padded furniture caninclude chairs, couches, sectional couches, ottomans, transit seating,seat wall tops, or other “site furniture” in architectural andlandscaping builds, etc. One suitable example for a padded couch isshown at 2300 in FIG. 23 . Couch 2300 includes three back cushions 2310,2320 and 2330 and three bottom cushions 2340, 2350 and 2360. We assumethere is a radiant seating panel under the seat cushions 2340, 2350 and2360 that is not visible in FIG. 23 . The result is a heated couch 2300that provides warmth to people sitting on the couch.

FIG. 24 shows a left side view of the back cushion 2310 and bottomcushion 2340 of couch 2300 in FIG. 23 , with the structural frameremoved for the sake of clarity. The bottom cushion 2340 sits atop theradiant seating panel 2410, which is supported by the structural frame.The radiant seating panel 2410 includes an insulative layer 2420 thatminimizes heat loss from the bottom of the seating panel 2410. Onesuitable example of insulative layer 2320 is Pro-DeX radiant barrierinsulation, which can be applied to the bottom of the radiant seatingpanel 2410 using a suitable adhesive. For a radiant table, having heatradiate downward from the tabletop can provide comfortable heat to aperson sitting at the table, as shown by the arrows facing down in FIG.1 , indicating heat radiating from the bottom of the tabletop 110. Forradiant seating panels, however, any heat that escapes in a downwarddirection is lost heat. The insulative layer 2420 is thus placed at thebottom of the radiant seating panel 2410 to minimize heat loss in thedownward direction. Note also a similar insulative layer could beapplied to the underside of the center portions of the tables shown inFIGS. 17 and 19 to minimize heat loss and could also be applied to thecenter portions of the tables shown in FIGS. 18 and 20 when the innerportions include the same concrete mix as the outer portions.

Heat from the radiant seating panel 2410 radiates up through the bottomcushion 2340 to a person sitting on the bottom cushion 2340. The bottomcushion is preferably made of materials that allow heat to easilyradiate from the radiant seating panel 2410 through the bottom cushion2340 to a person sitting on the bottom cushion 2340. The back cushion2310 in FIG. 24 is shown in a position for someone to sit down on thebottom cushion 2340. The back cushion 2310 can be pivoted down tooverlie the bottom cushion 2340, as shown in FIG. 25 . In thisconfiguration the back cushion 2310 serves as an insulator to maintainheat radiated from the radiant seating panel 2410 in the bottom cushion2340. The back cushion 2310 can be attached to the frame of the couchwhen in the sitting position shown in FIG. 24 using straps and/orsuitable fasteners such as snaps or hook and loop fasteners. Inaddition, the back cushion 2310 and bottom cushion 2340 can be attachedtogether at the back using straps and/or suitable fasteners such assnaps or hook and loop fasteners.

Specific configurations of the back cushion 2310 and bottom cushion 2340within the scope of preferred embodiments are shown in thecross-sectional views in FIGS. 26 and 27 . The bottom cushion 2340preferably has a mesh bottom surface 2620 that allows heat to easilypass from the radiant seating panel upwards into the bottom cushion2340. Phifertex is one suitable type of vinyl mesh for mesh bottomsurface 2620. The bottom cushion 2340 has an interior portion 2630 thatis preferably open-cell foam, thereby allowing heat to easily rise fromthe radiant seating panel 2410 through the bottom cushion 2340. Note,however, other materials may also be used. For example, a closed-cellfoam may not transfer heat with the same efficiency as open cell foam,but the lesser heat transfer may be a tolerable tradeoff for having amore comfortable bottom cushion 2340. The open cell foam is preferablycovered by an outdoor fabric 2640 that is preferably polyester oracrylic that is sewn or otherwise attached to the mesh bottom surface2620. The result is a bottom pad 2340 that transfers heat well and willdry quickly when it gets wet.

The back cushion 2310 preferably includes an exterior of outdoor fabricsuch as polyester or acrylic, with an interior 2650 made of batting orquilting material that provides padding. In one suitable implementationas shown in FIG. 26 , the interior 2650 may have one or more layers ofquilting material above and one or more layers of quilting materialbelow a reflective barrier 2660 to provide a padded back cushion 2310.The reflective barrier 2660 redirects heat received from the radiantseating panel 2410 through the bottom cushion 2630 back to the bottomcushion 2630, as shown by the arrows facing down in FIG. 26 , whichresults in the bottom cushion 2630 and lower portion of the back cushion2310 holding most of the heat radiated by the radiant seating panel2410. One suitable reflective material that could be used for thereflective barrier 2660 is Polytherm. The construction of the bottomcushion 2340 and back cushion 2310 enhance the function of a heatedcouch. The back cushion 2310 can be pivoted down on top of the bottomcushion 2630 as shown in FIG. 26 . In this position, the back cushion2310 acts as an insulator to trap heat released by the radiant seatingpanel 2410 until a person wants to sit down, at which time the personpivots the back cushion 2310 up to the position shown in FIG. 27 andsits down on the bottom cushion 2340. Because the back cushion 2310 wasreflecting the heat from the radiant seating panel as shown in FIG. 26 ,both the bottom cushion 2340 and the back cushion 2310 will feel warm tothe person who sits down. The reflective barrier 2660 will then reflectthe body warmth of the person who sits down, thereby maintaining atemperature in the back cushion 2310 that is higher than a coolerambient air temperature. The back cushion 2310 can thus act as aclamshell top, holding in the heat when in the lower position as shownin FIG. 26 until a person wants to sit down, at which time the backcushion is pivoted to the position shown in FIG. 27 , allowing theperson to sit down. The back cushion 2310 preferably includes one ormore straps 2710 that allow the back cushion 2310 to be tied orotherwise attached to a structural frame of the couch. The strap 2710may include any suitable attachment device, including without limitationsnaps, hooks and hook-and-loop fasteners.

An alternative configuration for the back cushion 2310 is shown in FIGS.28 and 29 . The top cushion 2310 in FIGS. 26 and 27 is a single piece,while the back cushion 2810 shown in FIGS. 28 and 29 comprises twoparts, a fixed back portion 2820 that is preferably attached to astructural frame for the couch, and a movable back portion 2830 that canbe pivoted between a lower position shown in FIG. 28 and an upperposition shown in FIG. 29 . The combination of the fixed back portion2820 and the movable back portion 2830 collectively make up the backcushion 2810. The movable back portion 2830 can have a constructionsimilar to back portion 2310 shown in FIGS. 26 and 27, with an outdoorfabric on the exterior, multiple layers of quilting material on theinterior for padding, and a reflective barrier layer 2860. In the mostpreferred implementation, the thickness of the movable back portion 2830is approximately half the thickness of the back portion 2310 shown inFIGS. 26 and 27 , and the thickness of the fixed back portion 2820 isapproximately the same thickness, resulting in an overall thickness forthe back cushion 2810 in FIG. 29 that is comparable to the thickness forthe back cushion 2310 in FIGS. 26 and 27 . The movable back portion 2830can be pivoted between the lower position shown in FIG. 28 and the upperposition shown in FIG. 29 . The movable back portion 2830 thus providesa clamshell-like function, holding in heat in the bottom cushion 2340when in the lower position shown in FIG. 28 , then providing a heatedcushion for a person's back and bottom when the person pivots themovable back portion 2830 to the upper position shown in FIG. 29 andsits down.

The movable back portion 2830 may be held in place against the fixedback portion 2820 via one or more straps 2870 or other attachmentdevices, which can include without limitations snaps, hooks andhook-and-loop fasteners, which can attach to either the fixed backportion 2820 or can attach directly to a structural frame for the couch.

The heated surfaces for radiant furniture as disclosed herein can bemade in any suitable thickness according to the particular application.For example, tabletops could be relatively thick to provide a strong andstable surface. Radiant seating panels that are covered by cushionscould be relatively thin to minimize the weight in a heated couch, forexample. In the most preferred embodiments, the thickness of the heatedsurfaces disclosed herein are preferably from 0.75 to 3 inches (19 to 76mm), are more preferably 1.0 to 2.5 inches (25 to 64 mm), and are mostpreferably 1.25 to 2.0 inches (32 to 51 mm). In some applications, suchas seating on half walls and other site furniture, the thickness couldbe much thicker than even 3 inches (76 mm). For example, a half walldesign as a seating area could have a heated surface thickness of 6inches (15 cm) or more. The disclosure and claims herein extend to anysuitable thickness for the heated surfaces in radiant furniture.

While circular tables, rectangular tables, and rectangular seatingpanels are shown in the drawings as suitable examples of radiantfurniture, the disclosure and claims herein expressly extend to anysuitable furniture piece with a heated surface in any suitable shape orsize. For example, square, rectangular, oval, hexagon, octagon,arched-shaped, or other shaped furniture can be radiant furniture asdisclosed herein. Picnic tables, site furniture, and bench seats areradiant furniture as disclosed herein. Chair backs and chair seats areradiant furniture as disclosed herein. One skilled in the art willrealize that virtually any piece of furniture could be made with aheated surface, and could thus be radiant furniture as disclosed herein.

Radiant furniture as disclosed herein has many advantages when comparedto propane space heaters. The cost of heating using radiant furniture issignificantly less than the cost of burning propane in propane spaceheaters. Radiant furniture provides very comfortable heat right where itis needed, thereby providing more uniform heat and avoiding having somepeople too hot and others too cold, which is common for propane spaceheaters. In addition, propane space heaters burn propane, and theburning typically causes very hot surfaces that are a burn hazard.Electric space heaters have most of the same burn hazards and utilizeextremely high wattage. Radiant furniture, on the other hand, iscomfortably warm without ever creating a burn hazard. Propane spaceheaters can be difficult to light, and both propane and electric spaceheaters typically require periodic maintenance, such as changing out thepropane tank, cleaning the heater, replacing elements, etc. Radiantfurniture, in contrast, requires virtually no periodic maintenance.Radiant furniture as disclosed and claimed herein therefore provides aheating solution that is vastly superior to known propane or electricspace heaters for the many reasons discussed above.

Radiant furniture made of a concrete mix includes one or more heatingelements or hot water supplied hydronic tubing that provide comfortableradiant heat. Tabletops can be heated to a temperature that iscomfortable for people seated at the table in a cool or cold outdoorsetting. Other tabletops can be heated to a lower temperature for use ina greenhouse or at an indoor location requiring a warm table, such as ina restaurant with the air conditioning set to a cold setting. Benchesand seats can be heated to provide comfortable heated seating.Combinations can also be used together, such as a heated tabletop withheated seats. A controller senses the temperature of the furniture andthe ambient temperature, then applies power to one or more heatingelements in the furniture according to programmed temperature thresholdsto provide comfortable radiant heat from the furniture. The controllerincludes a calibration mode that allows calibrating the controller to aparticular heated surface. The controller further comprises a knob thatdetermines an operating mode for the controller and allows adjusting atemperature threshold for the heated surface up or down.

While the specific examples herein disclose a controller driving asingle heating element in a heated surface, these are shown by way ofexample and are not limiting. The disclosure and claims herein expresslyextend to a controller that can drive multiple heated surfaces. Forexample, a radiant couch could include a radiant seating panel as shownin FIGS. 26-29 , and could additionally include a second radiant heatingpanel that heats the top cushion, thereby providing both a heated bottomand back. A sectional couch could have two separate radiant seatingpanels that are both driven by the same controller. The disclosure andclaims herein extend to a controller that can control multiple heatedsurfaces, which can be either in the same piece of radiant furniture orin different pieces of radiant furniture.

The disclosure and claims herein support an apparatus comprising: afirst temperature sensor interface; a second temperature sensorinterface; a heating element interface; and controller logic thatdetermines from a first temperature sensor in a heated surface that iscoupled to the first temperature sensor interface when a temperature ofthe heated surface is less than a first temperature threshold, and inresponse, applies power to a heating element in the heated surface thatis coupled to the heating element interface, and when the temperature ofthe heated surface is not less than the first temperature threshold,removes power from the heating element in the heated surface, whereinthe controller logic determines from a second temperature sensor coupledto the second temperature sensor interface a temperature in an ambientenvironment external to the heated surface, and dynamically adjusts thefirst temperature threshold as temperature of the ambient environmentchanges.

The disclosure and claims herein further support radiant furniturecomprising: (A) a heated panel comprising: a concrete mix; a heatingelement embedded in the concrete mix that provides a plurality ofnon-overlapping runs in the heated panel; and a first temperature sensorthat determines temperature of the heated panel; (B) a secondtemperature sensor that determines temperature of an ambient environmentexternal to the heated panel; (C) a controller that comprises: a knobthat includes an OFF position, and ON position, and an AUTO positionbetween the OFF position and the ON position; a mode selection circuitthat specifies one of a plurality of operating modes that eachcorresponds to a different type of heated surface, and further specifiesa calibration mode; a table of ambient temperatures and correspondingtemperature thresholds for each type of heated surface selectable by themode selection circuit; controller logic that reads the mode selectioncircuit and determines from the mode selection circuit a type of heatedsurface based on the selected operating mode and when the controllerlogic is in calibration mode; when the controller logic is incalibration mode, the controller logic: sets a temperature threshold toa default temperature threshold for the selected operating mode;receives input from a knob that includes a plurality of positions thatspecify an offset for the default temperature threshold; and writes atemperature correction value corresponding to the input from the knob toa non-volatile memory in the controller.

The disclosure and claims herein additionally support radiant furniturecomprising: a heated panel comprising a first temperature sensor thatdetermines temperature of the heated panel; a second temperature sensorthat determines temperature of an ambient environment external to theheated panel; a controller that comprises: a knob that includes an OFFposition, and ON position, and an AUTO position between the OFF positionand the ON position; a mode selection circuit that specifies one of aplurality of operating modes that each corresponds to a different typeof heated surface, and further specifies a calibration mode; a table ofambient temperatures and corresponding temperature thresholds for eachtype of heated surface selectable by the mode selection circuit;controller logic that reads the mode selection circuit and determinesfrom the mode selection circuit a type of heated surface based on theselected operating mode and when the controller logic is not incalibration mode; when the controller logic is not in calibration modeand the knob is between the OFF and the ON position, the controllerlogic reads the temperature of the ambient environment from the secondtemperature sensor, determines a corresponding temperature thresholdcorresponding to the ambient temperature in the table, and sets atemperature threshold for the controller logic that is adjusted by anadjustment value, if any, on the knob.

The disclosure and claims herein further support a method for providingradiant heat in a furniture piece comprising: providing a furniturepiece comprising: a heated surface that includes a first heating elementand a first temperature sensor that determines temperature of the heatedsurface; providing a second temperature sensor that determinestemperature of an ambient environment external to the heated surface;and providing a controller coupled to the first heating element, to thefirst temperature sensor, and to the second temperature sensor, thecontroller comprising controller logic that determines from the secondtemperature sensor a temperature of the ambient environment, thendetermines from a table of ambient temperatures and correspondingtemperature thresholds a target temperature threshold that correspondsto the temperature of the ambient environment, then adjusts the targettemperature threshold according to a value on a knob coupled to thecontroller logic.

One skilled in the art will appreciate that many variations are possiblewithin the scope of the claims. Thus, while the disclosure isparticularly shown and described above, it will be understood by thoseskilled in the art that these and other changes in form and details maybe made therein without departing from the spirit and scope of theclaims.

1. Radiant furniture comprising: (A) a heated panel comprising: aconcrete mix; a heating element embedded in the concrete mix thatprovides a plurality of non-overlapping runs in the heated panel; and afirst temperature sensor that determines temperature of the heatedpanel; (B) a second temperature sensor that determines temperature of anambient environment external to the heated panel; (C) a controller thatcomprises: a knob that includes an OFF position, and ON position, and anAUTO position between the OFF position and the ON position; a modeselection circuit that specifies one of a plurality of operating modesthat each corresponds to a different type of heated surface, and furtherspecifies a calibration mode; a table of ambient temperatures andcorresponding temperature thresholds for each type of heated surfaceselectable by the mode selection circuit; controller logic that readsthe mode selection circuit and determines from the mode selectioncircuit a type of heated surface based on the selected operating modeand when the controller logic is in calibration mode; when thecontroller logic is in calibration mode, the controller logic: sets atemperature threshold to a default temperature threshold for theselected operating mode; receives input from a knob that includes aplurality of positions that specify an offset for the defaulttemperature threshold; and writes a temperature correction valuecorresponding to the input from the knob to a non-volatile memory in thecontroller.
 2. The radiant furniture of claim 1 wherein, when thecontroller logic is not in calibration mode and the knob is between theOFF and the ON position, the controller logic reads the temperature ofthe ambient environment from the second temperature sensor, determines acorresponding temperature threshold corresponding to the ambienttemperature in the table, and sets a temperature threshold for thecontroller logic that is adjusted by the temperature correction valueand an adjustment value, if any, on the knob.
 3. The radiant furnitureof claim 2 wherein, when the controller logic is not in calibration modeand the knob is in the ON position, the controller logic reads a defaulttemperature threshold corresponding to the selected operating mode, andsets the temperature threshold for the controller logic to the defaulttemperature threshold adjusted by the temperature correction value. 4.Radiant furniture comprising: a heated panel comprising a firsttemperature sensor that determines temperature of the heated panel; asecond temperature sensor that determines temperature of an ambientenvironment external to the heated panel; a controller that comprises: aknob that includes an OFF position, and ON position, and an AUTOposition between the OFF position and the ON position; a mode selectioncircuit that specifies one of a plurality of operating modes that eachcorresponds to a different type of heated surface, and further specifiesa calibration mode; a table of ambient temperatures and correspondingtemperature thresholds for each type of heated surface selectable by themode selection circuit; controller logic that reads the mode selectioncircuit and determines from the mode selection circuit a type of heatedsurface based on the selected operating mode and when the controllerlogic is not in calibration mode; when the controller logic is not incalibration mode and the knob is between the OFF and the ON position,the controller logic reads the temperature of the ambient environmentfrom the second temperature sensor, determines a correspondingtemperature threshold corresponding to the ambient temperature in thetable, and sets a temperature threshold for the controller logic that isadjusted by an adjustment value, if any, on the knob.
 5. The radiantfurniture of claim 4 wherein the temperature threshold is furtheradjusted by a temperature correction value for the heated paneldetermined during calibration of the controller to the heated panel. 6.A method for providing radiant heat in a furniture piece comprising:providing the furniture piece comprising: a heated surface that includesa first heating element and a first temperature sensor that determinestemperature of the heated surface; providing a second temperature sensorthat determines temperature of an ambient environment external to theheated surface; and providing a controller coupled to the first heatingelement, to the first temperature sensor, and to the second temperaturesensor, the controller comprising controller logic that determines fromthe second temperature sensor a temperature of the ambient environment,then determines from a table of ambient temperatures and correspondingtemperature thresholds a target temperature threshold that correspondsto the temperature of the ambient environment, then adjusts the targettemperature threshold according to a value on a knob coupled to thecontroller logic.
 7. The method of claim 6 wherein when the temperatureof the heated surface is less than the adjusted target temperaturethreshold, the controller applies power to the heating element in theheated surface, and when the temperature of the heated surface is notless than the adjusted target temperature threshold, the controllerremoves power from the heating element in the heated surface.